I’ve already written about Delhi in a previous article, about how it’s really the smoggiest and dirtiest city in the world, and how this polluted atmosphere has turned the innocuous facemask into a basic commodity that’s also in woefully short supply. The example of Delhi ought to be enough to hammer the lesson into everybody’s heads about the devastating effects of air pollution caused by fossil fuel engine exhaust. I probably won’t have to rehash the numerous other things said about this topic, other than a piece of news that shows that some communities are taking steps to address it.

BBC reports that the leaders of four of the world’s major cities (and national capitals to boot) have made a joint resolution to implement a comprehensive ban on all diesel-engine vehicles – cars and trucks – upon their city streets, to be fully realized sometime around the year 2025. They hope that this strict stance will enable them to vastly improve the overall air quality in their respective communities. The resolution was committed to at theC40 biennial international gathering of global city leaders byMadrid, Paris, Athens and Mexico City, which served as host for the event.

Plenty of hard evidence was at hand for the four cities to make their case for such a concerted commitment. A recent report by the World Health Organization (WHO) indicates that an astonishingthree million people die every year whose deaths are linked to the heavily polluted outdoor air. And the most contributing factor to this deterioration of the air was pegged as motor engines that burn diesel oil, which produces large amounts of toxic nitrous oxide (NO) fumes and tiny particulate matter (PM), which can get into the lungs to wreak so much cardiovascular havoc to the point of death.

It was for these reasons that the mayors of Mexico City, Paris, Athens and Madrid made their solemn declaration to ban alldiesel vehicles in their cities by the middle of the next decade. To alleviate the significant loss in transportation, they have also committed to provide significant incentives in the widespread use of alternative power, such as electric, hydrogen and hybrid engine cars. In addition, the city leaders also hope to promote healthier options for commuters like bicycle infrastructure and pedestrian walking.

Already some of the cities in question have made strides towards their stated 2025 goal. Pariscloses their Champs Elysees main thoroughfare once a month to reduce traffic, and has turned a motorway running along the Seine River into a pedestrian-only walk. C40 summit host Mexico City Mayor Miguel Angel Mancera remarks of his own city’s efforts,"By expanding alternative transportation options like our Bus Rapid Transport and subway systems, while also investing in cycling infrastructure, we are working to ease congestion in our roadways and our lungs."